Vehicular or automotive mirrors have a field of view (FOV) that is the total viewing angle of the mirror. The FOV depends on the position of the viewer, the position of the mirror, the angle of the mirror, the radius of curvature of the mirror and the size of the mirror. In the United States planar mirrors are required on the driver's side of the vehicle, while convex mirrors (spherically curved) are allowed on the side opposite the driver. In Europe it is common to use what is known as aspheric mirrors. These mirrors typically have a spherical curvature for most of the mirror and then transition to a changing and tighter radius in the outboard portion of the mirror. The aspheric design has been used for many years in Europe to eliminate or reduce the driver's blind spot. The blind spot typically is located between the image viewed at the outermost portion of the side mirror and the driver's peripheral vision. In the United States aspheric mirrors are not allowed as a feature on new vehicles on the driver's side of the vehicle. The requirement in the United States is that a specified FOV must be met using a driver's side mirror with unit magnification. This results in flat driver's side mirrors. In contrast, on the passenger's side of the vehicle, a convex mirror is permitted by law. Still, a blind spot typically exists on the passenger's side of the vehicle.
A mirror known as “spotter mirror” is typically a convex mirror with a radius of curvature less than 500 mm, although a mirror with a larger radius of curvature or even a flat spotter element can be effective if the angle of the mirror is adjusted in such a way to provide additional FOV for the driver. The smaller the radius of curvature of the spotter mirror element, the greater the resulting FOV of that mirror provided all other variables are being held constant. A smaller radius mirror also reduces the size of the viewed image, so it can becomes increasingly difficult to see the image in the mirror. A spotter mirror may also be an aspheric mirror or any mirror that provides an increased FOV when compared with a standard mirror. The spotter mirror can be added to either side of the vehicle.
The alignment of the spotter mirror image with the image viewed in the standard mirror effects the FOV and the resulting blind spot. The blind spot is that area to the side and rear of the vehicle which may not be visible to the driver when using a conventional planar-type vehicle mirror. The image viewed in the spotter mirror element can overlap with that of the standard mirror, or the image could be discontinuous leaving a small blind spot between the two images.
Most spotter mirrors known in the art have an overlap region created by the spotter and standard mirror images. The FOV, the blind spot, and the overlap of the images are all affected by the position of the mirror and the position of the driver. If a driver chooses to angle the mirror away from the side of the vehicle or towards the side of the vehicle, the FOV, the blind spot, and the amount of overlap will change.
Some spotter mirrors are connected to the standard mirrors so when the standard mirror is repositioned, the spotter mirror is repositioned with it. Even in this case, the FOV, the blind spot, and the amount of image overlap will change. In the configuration when the spotter mirror is fixed or moves independently from the standard mirror, the changes will typically be greater.
Prior art spotter-type mirrors can also include those using a faceted or Fresnel spotter mirror where the spotter mirror element is positioned below and/or under the conventional mirror. Some mirrors are the aftermarket type enabling the user to stick-on the spotter mirror element to the surface of a preexisting mirror. Still other spotter mirror elements are arranged such that a portion of the mirror overlaps the conventional mirror or is oriented in a side-by-side relationship. Still others require mirror separation such that the front surfaces of the planar and spotter mirror elements are generally coplanar with one other. These types of mirrors also do not typically include any means to defrost or de-ice the mirror in the event of cold and moist conditions which would obstruct the driver's view and prevent the mirror from operating properly.
Additionally, there are some spotter mirror systems that are used in connection with recognition enhancement devices that operate to enhance a driver's recognition of an object in the blind spot. These systems work using an electronic device that is actuated upon detection of the object in the vehicle's blind zone. These types of mirrors are intended to effectively draw the operator's visual attention to the spotter mirror when vehicles or other objects enter the vehicle blind spot. Similarly, other mirrors and their associated components such as U.S. Pat. Nos. 7,349,143, 7,342,707, 7,324, 261, 7,306,355, 6,441,943, 6,244,716, 6,523,976, 6,521,916, 6,441,943, 6,335,548, 6,132,072, 5,803,579, 6,229,435, 6,504,142, 6,402,328, 6,379,013, 6,359,274 5,151,824, 6,244,716, 6,426,485, 6,441,943, 6,356,376, 5,448,397, 6,102,546, 6,195,194, 5,923,457, 6,238,898, 6,170,956 and 6,471,362 have been disclosed in the art and all of which are incorporated by reference in their entirety.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.